Golf ball and method of making



May 2, 1933.

H. K. B. DAVIS GOLF BALL AND METHOD OF MAKING Filed March 3, 1931 INVENTOR.

Patete ay a rest HENRY K. B. DAVIS, 0F

tilv 0, CONNECTICUT, ASSIGNOR 0F ONE-1E TO WILLIS H. BOOTH, OF NEW YORK, N. Y.

@0141? BALL AND THOD 0F Application filed March 3, 1981. Serial No. 519,765.

The present invention relates to playing balls, and more particularly to golf balls and a method of making them.

In the manufacture of golf balls, it has been customary to provide a suitable core, usually a spherical shell with a substance therein either in solid or liquid condition. The core is wrapped with rubber thread or ribbon, under as much tension as is feasible, while maintaining uniform tension without breaking the thread. When the core has been wrapped to the proper size, two hemispherical shells, usually of balata, are placed about the core within a mold which is heated suficiently to vulcanize the two parts of the cover together, and to soften the balata on the inner side thereof to obtain an amalgamation between the cover and'the rubber thread; that is, to permit the cover material on the inner surface thereof to penetrate between the wrapped rubber threads and adhere thereto.

' The severe heating necessary to obtain such a union between the cover and wrapped core decreases the tension in the rubber thread of the core and otherwise impairs its condition. The additional time required to effect the penetration and adhesion of the cover and threads slows up production and is, therefore, objectionable; but the more serious objections are the defects in, and the poor quality of the balls produced. Golf balls, manufactured by this and other methods, do not have suficient tension in the covers thereof nor the proper construction to afi'ord maximum resistance to shocks, or to afford maximum flight when played. If the cover is cut, the threads in the outer layer of the core are out also, or injured. Since these elastic threads are attached to the cover, they pull the out parts of the cover apart, causing the cover to break from the inner wrapped part, thereby making the ball useless for further accurate play. Uniformity in manufacturing is not possible and the character and hardness of the ball, as well as the tension in the cover, vary considerably. lit is, accordingly, necessary to grade the balls into several classes, a certain percentage of which can be sold as high grade balls, others as second grade, and others as low grade, or defective,

An object of the present invention is to im prove the quality of golf balls.

Another object of the invention is to provide a golf ball adapted to give maximum flight when played.

Another object of the invention'is to provide a ball adapted to have greater durability and toughness, thereby having a longer life. -Another object of the invention is to produce a ball adapted to give the sharp sound when hit, characteristic of the best balls.

Another object of the invention is to provide an improved method of manufacturing golf balls.

Another object of the invention is to provide a method of raising the grade of poorly wound and inferior balls so that they compare favorably with the highest grade balls.

Another object of the invention is to improve the molding operation by applying the cover without materially injuring the wrapped thread.

A further object of the invention is to shorten the time required for the molding operation, thereby producing economy in manufacture and a better ball.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not specifically referred to herein will oecur to one skilled in the art upon employment of the invention 1n practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accom panying drawing, forming a part of the specification, wherein Fig. 1 is a diagrammatic view illustrating one means for injecting a fluid into a golf ball; and

Fig. 2 is a fragmentary view illustrating a golf ball within a mold for securing the cover thereto.

The quality of golf balls is judged, primarily, by the distance of flight with a given impact, by the hardness of the ball and by the tightness and toughness of the cover. The distance of flight may be determined by playing a series of balls with a driving machine and obtaining the average distance of flight. The hardness of the ball is determined partly by the feel and partly by the sound which it makes when it is hit The harder balls give a sharp sound characteristic of the best class of balls. The toughness of the ball, particularly the cover, determines its durability. This is usually tested by sub- ]ectingthe balls to what is'called the guillotine test, where a sharp object is allowed to hit the ball a definite blow and the cut or bruise noted.

Certain features of the present invention tend to improve the usual finished ball as it leaves the mold by minimizing the impairment, by heat, of the wrapped core, and another important part of the invention is to minimize the effect of cuts in the cover of the ball, occasioned during play. A further important feature of the invention is to fur- Eher improve balls after the molding opera- A simple device is shown diagrammatically in Fig. 1, illustrating one method of treating balls in accordance with the present invention. A holder 1 is shown in section and may comprise a metal casting or other object having a recess 2 therein conforming to the shape of the ball 4. An injector 5 is provided with a cylinder or barrel 6, having a needle 7 at its lower end adapted to pierce the outer cover of the ball and to conduct a fluid 8 intosubstantially the center of the ball. Any suitable means may be utilized for forcing the fluid from the cylinder 6; as here shown, such means may comprise a piston 9, with a piston rod 10 which may be operated by hydraulic pressure, by screw action or by any other suitable means. Any suitable fluid, for example white lead, may be used in the injector.

The golf ball 4 may have any suitable construction; for example, it may comprise a central core 11, as illustrated in Fig. 1, filled witha fluid 12 and wrapped with a rubber thread or band 14. The liquid 12 in the core may be frozen in order to facilitate winding, which is usually done at the highest tension feasible without occasioning frequent breaks. Thereafter, the two hemispherical parts forming the cover are vulcanized together about the core, as illustrated in Fig. 2.

After the molding or vulcanizing operation for securing the cover 'on the ball, one feature of the present invention contemplates 'expanding the wrapped core to subject the molded cover to proper tension. This may be accomplished in any suitable manner, preferably by the injection of a fluid into substantiallythe center of the ball, and preferably within the core 11, as illustrated in Fig. 1, thereby to expand the wrapped core firmly against the cover and to place the cover under a tension which is substantially in excess of the tension which remains therein as a result of the molding operation. In this way, the ball is harder and the wrapped core is pressed firmly against the cover, thereby improving very materially the quality of the ball. Driving tests have indicated that the ball has a greater flight when thus treated. Guillotine tests have indicated greater durability and less tendency for the cover, when cut, to protrude from or leave the core when thus treated. The high grade balls are improved, when thus treated, and the lower grade balls are materially improved and compare favorably with the higher grade balls. Ordinarily the aperture, made by the injecting needle, automatically closes itself, the aperture being sufliciently small that it is not noticeable in the cover of the ball. If desired, the aperture may be filled in any suitable manner.

For convenience, a pressure gauge 15 is attached to the cylinder 6 so that the exact pressure within the ball may be definitely determined. In this way, each ball can be made to have the same internal pressure, which will produce uniform characteristics in both the distance of flight and the hardness of the ball. This also enables a retailer to adjust the tension of the cover and the hardness of the ball to suit the individual taste. Some players like an extremely hard ball, but tests have indicated 'that a ball with an internal pres sure of about 1500 pounds per square inch produces excellent results, although greater pressures are desirable in some instances. This is an increase of several hundred pounds over and above pressures which exist in the highest grade balls at the present time. The maximum internal pressures that can be obtained by the present winding and molding operations are limited and are considerably below the desired range. The tension, if any, in the cover of golf balls is very small under known methods and, in many cases, there is no tension whatever.

While the invention described above is applicable to the present commercial balls, very important advantages can be obtained by the particular method of molding about to be described. In Fig. 2 there is shown the usual form of mold 17 for golf balls, which may be heated by steam passing through conduits 18. This mold may be the same as the molds commonly used, and hence, a detailed description is not necessary. The hemispherical shells forming the cover, if desired, may be preheated so that they become relatively soft and form a close union between the wrapped core and the cover. I'he advantage in prc Leonor? heating the cover to get a close union with the core is that the period of time necessary for Vulcanizing the two hemispherical parts together may be decreased from about six minutes to one minute. The decrease in molding time not only shortens the molding period and produces economy in manufacturing, but also minimizes the period to which the thread is subjected to heat. The stretched rubber deteriorates rapidly under the degree of heating encountered in this operation, therefore the decrease in the molding period leaves the inner part of the ball in a much better condition. At the same time, the union of the cover with the ball is tight and secure, without substantial penetration of the cover material into the interstices of the mapped core, thereby avoiding impairment of the ball by reason of undue heat and by reason of adherence of the thread to the cover. Balls made in this manner may also be treated, as described above, with an injector which increases the pressure Within the ball.

The preheating of the hemispherical shells may be omitted without increasing the molding period, and good results obtained because the increase in pressure within the center of the ball and the expansion of the wrapped core subsequent to the molding operation press the cover firmly against the ball. The decreased molding period increases production and, in addition, produces a much better ball because the wrapped core is not subjected to sufficient heat to impair materially the elasticity of the rubber therein. A'ball manufactured in this manner, with the decreased heating period, will have greater elasticity and will have a greater distance of flight, as well as other advantages. lit has been found that the amalgamation of the cover and the wrapped core is not necessary. lln fact, the rubber, if amalgamated with the cover, may tend to pull open the cover when the cover and threads are cut.

Tn certain cases, it may be desirable to have the ball slightly underweight and undersize so that the ball, after the injecting operation, will conform rigidly to the usual standards As a matter of fact, the increase in size of the ball is relatively slight, as well as the increase in weight, and the injecting operation can be applied to ordinary commercial balls without changing them suficiently to make them objectionable from the standpoint of size or weight.

It will be seen that the present invention provides a method of treatment Which may be applied to ordinary commercial golf balls to improve their playing qualities and their durability. The resulting balls have all the characteristics of high grade balls, even where the winding and molding operations are such as to produce an inferior ball. The invention may beutilized by the manufacturers, and the balls improved before they are sold to retailers, or the invention may be utilized by stores or club professionals to increase the tension in the cover to conform to the taste of the buyers. The increase in the size of the wrapped core produces a close union between the core and the cover, and the effectiveness of such union can be increased by preheating the shells of the cover prior to their application and by reducing the molding period. Shortening the molding period also increases production, but the more important effect is to minimize the impairment of the outer threads on the core as a result of the molding operation.

As various changes may be made in the method of expanding the ball after molding the cover and in the form, construction and arrangement of the parts herein Without departing from the spirit and scope of the invention and without sacrificing its advan tages, it is to be understood that all matter herein is to be interpreted as illustrative and not in a limiting sense;

Having thus described my invention, it claim:

1. fThe method of improving golf balls, which method comprises piercing the cover of a finished ball and injecting sufficient fluid therein to subject the cover of the ball to tension.

2. The method of improving golf balls, which method comprises injecting a fluid into substantially the center of a finished ball and discontinuing said injection of fluid when the pressure in the center of the ball has reached a predetermined amount.

8. The method of improving golf balls, which method comprises expanding the wrapped core of a golf ball into intimate contact with the cover by injecting a liquid into the ball to expand the cover and to in gregse the tension in the molded cover of the d. The method of making golf balls, which method comprises molding a cover about the inner core, permitting the cover to cool, and thereafter injecting fluid through the cover into the ball to subject the cover totension.

5. The method of making golf balls, which method comprises applying a cover about the inner core and thereafter injecting a fluid through the cover into substantially the center of the ball to increase the pressure therein.

6. The method of making golf balls, which method comprises providing a core having a fluid center, applying a cover about said core and thereafter injecting a fluid, similar to the fluid in the center of the core, through the cover into the core to increase the fluid pressure therein.

7. The method of applying a cover to golf balls, which method comprises subjecting the cover part to sufficient temperature to form a union therebetween, and thereafter injecting a fluid into the ball to increase the size of the core sufliciently to give proper tension to the cover of the ball.

8. The method of manufacturing golf balls, which method comprises molding the cover about the wrapped center without substantial adhesion therebetween.

9. The method of manufacturing golf balls, which method comprises providing a core, preheating the cover to be applied to the core 50 that the cover is relatively soft, applying the cover to the ball in a preheated state, and subjecting it to further heat in order to form a union between the parts thereof.

10. The method of manufacturing golf balls, which method comprises providing a core, preheating the cover to be applied to the core so that the inner surface thereof is relatively soft, applying the cover to the ball in the preheated state, subjecting it to further heat in order to form a union between the parts thereof, and thereafter injectinga fluid into the ball to increase the size of the core and to apply proper tension to the cover.

11. The method of making golf balls, which method comprises making a ball having a cover with less than the desired tension therein, and thereafter subjecting the cover to greater tension after the cover is molded thereon.

12. The method of making golf balls, which method comprises making a ball slightly underweight, slightly undersize and having insuflicient tension in the cover thereof, and thereafter injecting fluid therein to produce a ball of normal weight and size and having a highly tensioned cover.

13. A golf ball comprising, in combination, a wrapped core, and a molded cover thereon,

' the outer threads of said core being substantially free from adhesion to the cover.

14. A golf ball comprising, in combination, a wrapped core and a molded cover thereon, the threads in said core being substantially unattached to said cover, thereby permitting the cover and threads to act substantially independently when the cover is impaired.

HENRY K. B. DAVIS. 

